I have had a call to know this in the past, but I did not put it to memory. How hot do you think it would have to get for a fiberglass hull to delaminate because of a fire on a boat in the slip next to it?
Depends on the composition of the hull. Cored hulls usually run into problems quicker, if a fire is nearby. Partly due the isolating effect, thus a hotter outer skin, and the core material itself can generate problems as well. Basicly up to 60-80 degrees C things in general are cosmetical, and can be corrected with some good polishing. Up to 120-150 degrees C some movement in the construction can occur, however from a structural point of view still nothing important. At this temperature cores can become problematic, however it takes a considerable amount of time for the heat to transfer to the core. (hopefully before that time the burning boat either got extinguished or sank) Above 150 degrees C, and up to 220-250 or so, gelcoat and first layers of laminate can start to give up, become brittle or start cracking. Above 220-250 degrees C a complete decomposition takes place. For burn-out tests (burning polyester resin out of a laminate, to determine the laminate stack) a temperature of 350 degrees C is used. At that temperature no polyester is left, and the glass fabrics or fibers can carefully be pulled apart and weighed, after which the laminate plan can be reconstructed.